Yes, there is - the tool is called “Symmetry” - third from right under the vertex modelling tab.
With your item selected, hit symmetry. Then you can either hover your mouse pointer on the side of your item that you want to copy it to - a blue plane will show up - click on the pane and it’s done. Instead of hovering your mouse pointer, you can look in the properties panel and select the axis you want it to copy to - in the case of a boot, it’ll be either X+ or X-.
In the properties panel, there are two icons for options. The one which has a plane sticking out of a cube lets you place the copy exactly where you want it - with that one selected, a blue line appears from the original, through the blue plane to a green dot. Move the mouse pointer and the green dot moves - when it’s where you want the copy to be placed, click.